Water treatment and composition



c; s. KING 2,395,126

WATER TREATMENT AND COMPOSITION Feb. 19, 1946.

1 Filed Jan. 25, 1944 A A YAVAYEZT if V Y 4 MOZAA PERCENT M1 0 Car/as 15117539 yW 6mm it r'zrey fzzven/or Patented Feb. 19, 1946 WATER TREATMENT AND COIWPOSITION Charles S. King, Joliet, 111., assignor to Blockson Chemical Co., Joliet, III., a corporation of Illinois Application January 25, 1944, Serial No. 519,633

8 Claims.

The present invention relates generally to treating water, and to a complex water-treating phosphate salt therefor. It relates particularly to a porous bed of such material and to flowing zvater through the bed to dissolve material there- The use of alka1i-metal salts of acid of phosphorus, such as metaphosphates, pyropho-sphates, and other polyphosphates, is well-known for treating hard water. Such salts are quite soluble and are unsuitable for practical use in a bed through which water may be passed for desirable periods of time without refilling. Not only do they dissolve readily, but being hygroscopic, they gel and congeal into a cake in a bed when water becomes stagnant therein or is even Lndmotion through the bed, thus clogging the It is an object of the present invention to provide complex salts of acid of phosphorus, characterized by desirable water-treating properties, by suitable solubility characteristics for water treatment, and by suitably slow or limited solubility for maintenance of a porous bed thereof for a considerable length f time both with water flowing through the bed and static in the bed.

It is an object of the present invention to provide an aluminum-containing complex watertreating salt of the kind referred to.

It is also an object to provide a suitable chemical salt bed and to pass water therethrough at a substantially constant rate to charge the water to a predetermined extent with material dissolved from the bed, either to treat the water so passing through the bed, or to add such so charged water to water to be treated.

It is a particular object of the invention to provide a bed of material through which water may be continuously passed while dissolving'not more than about 1% by weight of the bed per hour, at temperatures not over about 25 C., regardless of the amount of water passing therethrough.

Various other and ancillary objects and ad-' vantages of the invention will appear from the following description and explanation of the invention, given in connection with the accompanying drawing in which:

Fig. 1 shows a trilinear diagram of 3-component compositions, and H Fig. 2 is a fragmentary enlargement of Fig. 1.

Reference is made to my copending applications, Serial No. 360,065, filed October '7, 1940, now U. S. Patent No. 2,370,473 of February 27, 1945, and a continuation-impartthereof Serial is less water-soluble because of the presence of the A1203.

There is also another property of these salts. A glass within the compositions such as (l) is hygroscopic with water. Particles of it wet with water will swell, and if in contact for short periods of time,will cement together or congeal. This property is gradually lost with loss of watersolubility, as effected by substituting some A1203 for some NazO. Use of such congealing particles, with or without said A1203, is not satisfactory for providing a bed through which to .pass

' water to dissolve bed material. Certain glasses do not congeal if the water is moving continuously, but if the bed with water in it becomes static, congealing tends to close up the bed, impairing its utility or rendering it useless.

I have determined that for a commercially suitablebed material, the particles of it must be non-congealing, so that emergency conditions leading to a static bed with water in it, will not prevent renewed operation of the bed. The composition as well as particle size affect the congealing tendency of the bed. I have alsodetermined that these two factors of size and composition also affect the rate or solution under controlled conditions; and I have determined that particles (whatever their size and their composition) are non-congealing, if they may be exposed at not over 25 C. with agitation to 5 times their weight of water for 24 hours with loss by disso lution of not more than about 25% of their weight, or in other words about 1% by weight per hour. i

In order to exemplify this, I have determined that a composition or 3-molar per cent A: and 48.5 molar per cent each of NazO and P205, in line mesh is congealing and too quickly soluble, while ina coarse mesh is suitably slowly-soluble and non-congealing. At a size of 10 to 20 mesh (per inch) in said test 100% dissolves in 10 hours. But as lumps of about .5 x 1 inch in size, only 5.5% dissolves in 24 hours.

Wherein the expression of size in the form such as "a: to 11 mesh (per inch) is used herein, it means that a mass of the particles pass through a screen having a: meshes per inch and are retained by a screen having y meshes per inch. But in larger sizes, commercial practice is not to use the "mesh" system, but to express size as of an averaged lump thereof, which averaged lump is not greater in any dimension than a large flgure (such as 1 inch in the designation .5 x 1 inch lump size) and not smaller in any dimen-' sion than a small figure (such as .5 inch in said designation) There are factors which limit the compositions, aside from the solubility. Thus, it is difilcult to make glasses by fusing ingredients, and chilling, where the proportional content of P205 present is less than that corresponding to tetraphosphoric acid. Thus, a line of tetraphosphates on a trilinear diagram of P205, Na20 and A1205, is one boundary line for suitable glass compositions.

Another limiting time is a line for P205 content on said trilinear diagram corresponding to metaphosphate salts, because where a proportional content of P205 is present which is greater than that corresponding to metaphosphoric acid, the dissolved salt is less stable, and forms too acid a solution. I

Increased content of sodium oxide leads to greater and faster solubility, which is lessened also as A1203 content increases. Increasing Na20 also increases undesirable hygroscopicity.

Said exemplary compositions having 3 molar per cent A1205 are within a special portion of the field of the present invention, of which field there are herein described three distinct portions. Since it was foundthat particle sizemay render a given composition suitable or unsuitable, it becomes necessary to define the useful materials of the present invention in terms of composition and of particle size. Consideration of the requirements of small and large beds, and consideration of the sizes produced in the commercial production of suitable glasses, have led to selecting a commercially practicable range of sizes from a lower limit of 10 to 20 mesh (per inch) to an upper limit of .5 x 1 inch lump size. This range accommodates both the producer, and the user of such glasses for beds. Selection of the range presents the problem of determining compositions to fit the range.

- In the accompanying drawing there is shown a diagram of which vertices III, II and I2 represent 100 molar per cent of-Na20, P205 and A1203, respectively. Line It represents compositions consisting of NazO and P205. Line ll represents compositions consisting. of A120: and P205. Line I! represents compositions consisting of A120: and Na20. Any point inside the triangle represents a composition of Na20, P205. and AIM.

On line It, the point it represents sodium metaphosphate represented by the formula (NaP:)= and consisting of equal molar portions of Na20 and P205. On line I, the point I! represents aluminum metaphosphate represented by the formula Al(PO5)a and consisting of 1 mole of A120: and 3 moles of P205. Hence, by connecting points It and H by line lfl, line l0 represents compositions which may be considered salts of metaphosphoric with metal consisting of sodium and aluminum.

Likewise point is on line It represen s sodium tetraphosphate having the empirical formula Na5P4015. and point 20 on line H! represents aluminum tetraphosphate having the empirical formula AlzP40ia. Hence, line 2| connecting points I9 and 20 represents compositions which may be considered salts of tetraphosphoric acid with metal consisting of sodium and aluminum.

As stated above, line I8 is a limit of glass compositions suitable for the present invention without beingtoo acid, but it is not a limit of compositions having readily made vitreous glass forms. And, as stated above, line 2! is a limit for readily made vitreous glass compositions, but it is not a limit relating to acidity or alkalinity of solution of the glasses for the present invention. Between lines l8 and 2| lie the compositions of the present invention. The general direction of the zone I 82l on the diagram indicates that downwardly, the contents of A120: and of P205 increase, and content of Na20 decreases. Also, it has been determined experimentally that downwardly in this zone i8-2l, solubility and hygroscopicity decrease.

Practical requirements call for compositions in the zone l8-2l which are not too insoluble and 7 not too soluble. Experiments with many granular compositions have shown that certain high solubilities and congealing tendencies in a bed of the composition are accompanying characteristics where the solubility, in the described test therefor, exceeds about 1 by weight per hour at 25 C. in water 5 times the weight of the composition being tested, when tested for 24 hours, if possible. Therefore, granulated compositions which exceed this solubility are excluded from the present invention.

The lower limit of solubility is not related to congealing characteristics, and in practice bears only on relative volumes of bed material and water, rate of flow, and the concentration of dissolved glass desired. Practical considerations of commercial sizes of beds, rates of flow, and

hardness of water commercially encountered, have led to considering as unsuitable those granular compositionsflwhich in said test for solubil-- said test have been determined, and from them certain ones have been selected for limiting the present invention when the sizes of the compositions are not finer on the average than 10 to 20 mesh (per inch) nor coarser on the average than .5 x 1 inch lump size. In the table below, under Item No., a numeral indicates the compositions on the diagram bearing such numeral on boundary line or intersections, and a letter indicates compositions anywhere on the diagram, either inside the shaded areas or outside thereof, or on a boundary line of the shaded areas.

The following table shows compositions so identiiied under "Item No." varying in the given molar percents of A1201, No.20 and P205, and shows the solubility of each at 10 to 20 mesh (per inch) or at .5 x 1 inch lump size, in terms of per cent by weight dissolved per hour of time, when 20 grams of the composition is agitated with grams of water at 25- C. for 24 hours. Where this given per cent per hour dissolved is more than 100%, as for example 400% per hour," it signifies that all of the composition dissolved in fifteen minutes. Hence, insuch a case the 24- another shaded at .5 x 1 .inch lump size which have described one bed-volume per minute.

ococoss can be replenished daily. Usinslesssolgllle material, it can bemade to operate for a weeko'r more without attention to refill it. By choice of the compositions of the present invention, there is no danger tothe bed from congealing when there has been any cessation-of the infable Mohrpuoent Pam 1mm. Biro dissolved Alt 10.0 no.

10 '10 to 20 mesh... 0. 5 40 66 .lixlinch 0. 2 40.26 01.75 10to20mesh.-- 1. 1.6 47.25 61.25 ..5xiinch.-- 1. 1.0 40.20 40.20 .0x1inch 1. 8.6 64.0 42.0 .6! 1 inch 1. 0.26 49.25 44.5 10 tommeshm. 1.

0.5 43.6 47.0 .6x1inch 0.01 Y 10 42.0 47.0 i00o00mesh..-- 0.01

0 00.0 00.0 10to20mesh. 000 0 50.0 00.0 .oxlinch 00 0 00.0 40.0 10 to 20 mesh-.- 1000 1 40.5 40.5 10to20meeh 300- 1 80.4 00.0 108120111 400 l 400 01.0 10 to 20 mean.-- 07 1 an 01.0 .Bxlinch 2.0 3 48.5 48.6 10to20mesh.-.. 10 3 48.6 48.6 .6! l 0.23 a 00.0 42.0 .0x1 ch as 6 40.0 66.0 10to20 0.042 6 40.0 65.0 .bxlin 0.01 .6 47. 6 47. 6 10 to 30 0. 88 0 47.0 41.0 .0: 1 inch 0.088 5 67.0 38.0 l0to20 25.0 7 48.0 46.0 .5! lin 0.031 10 so. 0 00. 0 10 to so 0. 01 10 00.0 00.0 .6! 1 in 0.002 10 46.0 46.0 10 to 20 0. 042 a 10 40.0- 40.0 .6x1in 0.012 10 04.0 00.0 100020 0.2 10 .420 47.0 .0110: 0.009

In the diagram of the drawins, the composi-.

tions 3042-36-40 define a shaded area of granular compositions at 10 to 20 mesh (per inch) which have described solubilities in the range from .01 to [1.0% by weight per hour. Likewise, 'compositiohs 4346--31 define area of ranular compositions solubilities in the-range from .01 to 1.0% by ,weight per hour. These two shaded areas overlap at area 3l-32-30- 31, which area defines compounds having the described solubility some-.-

line al as-must be used at 10 to 20 mesh, and,

as the composition moves above the line 30 -08 it may be coarser and be .5 x 1 inch lump size ,on'

' line Sl-fl. On the top end, compositions on lines 33-46-36 must be at .6 x 1 inch lump size, and as the composition moves below this boundary line 33-36-36it may be flner and be at 10 to 20 mesh (per inch) on line 3248.-

Thus, it is seen that composition together with granulation, are controlling factors for meeting the criteria of solubility herein employed. The

eflect of changing granulation for a fixed composition is shown in the table in numerous pairs of items. In particular, the pair G and N, is referred to, because the described solubility is increased 10-fold by merely grinding material 005 x 1 inch lump size to 10 to 20 mesh (per inch).

In practical operation, the above described solubilityv test is comparable to flowing water at 20 to 25 C. through a bed of the tested material for 2 1 hours at a rate of one bedwolume per minute. For convenience, to correlate operation oi a bed with the test for selection of material, preferably a commercial bed is designed iorfiow oi water therethrough at a rate of at least about For the less soluhle compositions the ratemay be higher than t bed-volume change per minute. oi" the most soluble compositions of the invention will lose about 25% content per day, and

tended normal continuous flow through the bed. 80 designed-and operated, such a bed is refillable at regular periods, preferably each week for the rate of flow as preferred above.

Example lated as 029.003, is determined by experiment to require addition to it to prevent-scale, of 1.5 to 2 parts per million of a glass composition of the present invention consisting. of

sanoisatnsioaasrios- Such a composition in .5 x 1 inch lump size, is

placed in a closed chamber having water inlet andoutiet pipes, providing a bed of 1 cu. ft. volume. This composition has a solubility of 23%- by weightper hour. Using a water rate of 3 bed-volumes per minute with'water at 20 C.,

15 parts of the composition per million of water goes into solution as the. water passes through the bed. Therefore, a portion of the water to thepreheater is by-passed through the bed at said rate, there being from to of the total water so by-passed in order to assure complete treatment of the water with avoidance of scale formation in the preheater. I Such a bed treats 1,700,000 lbs. of water per day. The bed material originally weighs about 100 lbs. and about I while the treated water at 80 C. for 4 hours pre- Thus, a bed 20 lbs. is dissolved per week. It is serviced weekly by adding about 20 lbs. of the same granular composition, an operation taking only about 10 minutes. When the flow through the bed is stopped for any reason and water becomes static in the bed, the water merely'becomes more concentrated at a low contentwith the composition, and the remnant. glass does not congeal.

In the example, the effectiveness position is indicated by the following comparison of heating the said cooling water without such treatment and with such treatment at 1.5 to 2 parts per million of the composition of the ex- I ample. The untreated water heated at C. for 4 hours, precipitated 20% of its hardness,

cipitated no hardness. The treatment for this test shows inhibition.

From the foregoing description and explanation, it will be understood that within the shaded areas, there are possible many compositions, of which'the size may be important, which may be placed into a bed for the passage of water therethrough for dissolving over conveniently long periods of time, a water-treating composition in small but eflective, and controllable, amounts.

The foregoing illustrations and examples are not intended to limit the invention short of its scope as expressed in the appended claims.

I claim:

1. A water-treating composition in the form of a water soiubie glass consisting analytically of Nazi), A1203 and P205, said coposition being substantially that represented by the area of a trilinear diagram of compositionsoi NE20, A120 and P205 which area is defined by the lines in series as follows: the metaphosphate line-the line of 10 molar per cent AlzOa-the tetraphosof the comphate line-the line between compositions: 3.5A12O3.5N&20.42.5P2O5 and the line of 1.5 molar per cent of NaaO, said compositions on the last two. lines being of granulation corresponding to .5 x 1 inch lump size, and said composition on the line of 1.0 molar per cent A1203 being of granulation corresponding to 10 to 20 mesh (per inch), and otherwise having a gran,- ulation varying between said lump size and said mesh and such that the solubility is in the range from .01 to 1.0% by weight per hour when a quantity of the granular composition is tested for 24 hours in 5 times its weight of water at 25 C.

2. The method of adding the water-treating substance of a water-soluble vitreous glass to water which comprises forming and maintaining a porous bed of a composition according to claim and l, and passing water through said bed at a substantially constant rate while dissolving substance of said glass into the water.

3. A water-treating composition in the form of a water-soluble glass consisting analytically of NazO, A120: and P205, said composition being substantially that represented by the area of a trilinear diagram of compositions of Na20, A1203 and P205 which area is defined by the straight lines connecting the four compositions in sequence as follows:

eauomomotsmm asaiioaeasnaioa'zeioi 625M203.49.25NB.2O.44.5P2O5 ZAlzOsAG.25Na2O.51.'75P205 a water-soluble glass consisting analytically of NazO, A1203 and PaOs, said composition being substantially that represented by the area of a trilinear diagram of compositions of NazO, A1203 and P205 which area is defined by the straight lines connecting the four compositions in sequence as follows:

5A12Oa.40Na2O.55PzO5 9.5A1203.43.5N2.20.47Pz05 10Alz0a.42.5Na20.4'7.5Pa0t A IOAIzOaBONaaOfiOPaOs the composition on the line defined by the last two of said compositions being of granulation corresponding to 10 to .20 mesh (per inch), the composition on the line defined by the first two of said compositions being of granulation ranging from a fine size of 10 to 20 mesh (per inch) to a coarse .5 x 1 inch lump size, and the composition otherwise having a granulation varying between said lump size and said mesh and such that the solubility is in the range from .01 to 1.0% by weight per hour when a quantity of the granular composition is tested for 24 hours in 5 times its weight of water at 25 C.

6. The method of adding the water-treating substance of a water-soluble vitreous glass to water which comprises forming and maintaining a porous bed of a composition according to claim 5, and passing water through said bed at a substantially constant rate while dissolving substance of said glass into the water. v

7. A water-treating composition in the form of a water-soluble glass consisting analytically of NazO, A1203 and P205, said composition being substantially that represented by the area of a trilinear diagram of compositions of NazO, A: and P205 which area is defined by the straight lines connecting the five compositions in sequence as follows:

a quantity of the granular composition is tested for 24 hours in 5 times its weight of water at 25 C.

8. The method of adding the water-treating substance of a water-soluble vitreous glass to water which comprises forming and maintaining a porous bed of a composition according to claim 7, and passing water through said bed at a substantially constant rate while dissolving substance of said glass into the water.

CHARLES 8. KING. 

